Automatic transmissions utilize a planetary geartrain and a plurality of coupling devices, i.e., clutches, to provide a plurality of different gear ratios, i.e., gear positions. In automatic transmissions having six (6) or more gear ratios, a single clutch is often utilized in multiple shifting operations to facilitate shifting between multiple gear ratios. For example, in a six speed automatic transmission, a single clutch may be utilized in independent shifting operations to shift the automatic transmission into a third gear ratio, a fifth gear ratio and a reverse gear ratio.
Each of these different shifting operations requires a different piston force, i.e., a different gain, applied to the single clutch in order to achieve a smooth shift into each of the different gear ratios. For example, in the six speed automatic transmission described above, a single clutch requires a lower piston force applied thereto, i.e., a higher gain, to shift into the third gear ratio than the fifth gear ratio, in order to achieve a similarly smooth shift into each of the different gear ratios. Therefore, higher resolution in pressure control is desired in controlling high gain clutches.